Company News: Three Peer-Reviewed Papers by ISA Pharmaceuticals Introduce Strategies to Improve Immunotherapy Against Cancer
– Local Delivery of Checkpoint Control Antibodies Greatly Improve Efficacy and Safety
– Promising Potential for Combinatorial Strategies
ISA Pharmaceuticals B.V., a clinical-stage immunotherapy company focusing on rationally designed therapeutic vaccines against cancer and persistent viral infections, today announced the publication of three peer-reviewed papers that demonstrate the benefit of local delivery of a checkpoint control antibody targeting CTLA-4 (cytotoxic T lymphocyte antigen-4) for the successful eradication of cancer and the reduction of side effects. The papers include a review that underlines the importance of strategies for combinatorial treatments to improve further the immunotherapy of cancer. ISA Pharmaceuticals is developing cancer immunotherapies along those lines, in particular its Synthetic Long Peptide (SLP®) vaccine ISA101 for the treatment of HPV-induced diseases, such as cervical cancer and head and neck cancer, and ISA203 for the treatment of various tumors including lung cancer, head and neck cancer, breast cancer and melanoma.
In a paper just published in Clinical Cancer Research , a team of scientists from Leiden University Medical Center (LUMC) and ISA Pharmaceuticals report that in preclinical mouse models of cancer, the injection of a CTLA-4 blocking antibody in a slow-release formulation close to the tumor is very effective in activating a systemic anti-tumor (CD8+) T cell response. CTLA-4 is a crucial immune checkpoint protein that down-regulates the body’s immune response. The low-dose local treatment (50μg subcutaneously in a slow-release vehicle) eradicates tumors, including distant tumors, as effectively as a high-dose systemic treatment (2×200μg intraperitoneally). The method also leads to a 1000-fold decrease of antibody levels in the serum, thereby reducing adverse events and the risk of autoimmunity.
These findings are supported by an increasing number of studies demonstrating that local targets, mainly present in the microenvironment of tumors and draining lymph nodes, are key players in tumor progression. As published in a second paper by researchers from LUMC and ISA, a review in the International Journal of Cancer , local immunotherapies have clear advantages over systemic treatments, both in their ability to shift tumor-promoting mechanisms towards effective tumor-eradicating immunity and in terms of reducing the risks of systemic administration.
In the third publication in Seminars in Immunology , current cancer immunotherapy approaches are reviewed, concluding that most standalone immunotherapeutic strategies either fail to affect progressive diseases and survival significantly – or only do so in a minority of patients. The authors support combinations of synthetic vaccines that stimulate tumor-specific T cell responses and adjuvants, immune-modulating antibodies, cytokines, or chemotherapy.
 Fransen MF et al. (2103), Clin Cancer Res, Published Online First June 20, 2013; doi: 10.1158/1078-0432.CCR-12-0781
 Fransen MF et al. (2013), Int. J. Cancer, 132: 1971–1976; doi: 10.1002/ijc.27755
 Arens R et al., (2013), Sem Immunol, Published Online First May 21, 2013;